Influenza (flu) |
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In 2015, an outbreak of avian influenza subtype H5N2 was identified in a series of chicken and turkey farming operations in the Midwestern United States. By May 30, more than 43 million birds in 15 states had been destroyed as a result of the outbreak, including nearly 30 million in Iowa alone, the nation's largest egg producer. In the Midwestern U.S., the average price of eggs had increased 120% between April 22 and May 30. The effects however were seen nationwide, with prices in California up 71% in the same timeframe. [1]
The virus was first identified in Minnesota in early March. Prior to April 20, it affected commercial turkey farms almost exclusively, in the states of Arkansas, Iowa, Missouri, North Dakota, South Dakota, Wisconsin, and at 28 farms in Minnesota, where the virus was initially identified.[ citation needed ]Migratory waterfowl are assumed to have brought the disease to the Midwest, but how it made its way into poultry barns is undetermined. [2] No human cases have been reported, and human infection is almost impossible.[ citation needed ]
On Monday, April 20, the U.S. Department of Agriculture announced that 5.3 million egg-producing hens at a northwest Iowa farm must be destroyed after the virus was confirmed. The number at this operation alone comprised a little over 1% of egg-laying hens in the United States. [3] This infection would be the first in a series at large hen operations in Iowa, Nebraska, and other states.[ citation needed ]
As of May 27, over 25 million chickens had either died of the infection or been euthanized in Iowa alone. [4] Nebraska's toll at the same date was 7 million—a majority of the state's 9.45 million egg-laying hens. [5]
This table shows large bird farm infections during the 2015 outbreak. All birds affected either died of the H5N2 infection itself, or were destroyed as a precautionary measure. While 205 total infections were confirmed through June 1, only larger outbreaks (affecting >200,000 hens or >50,000 turkeys) are displayed here.
Date detected | Location | Birds affected | Type | Source |
---|---|---|---|---|
March 27 | Lac Qui Parle County, Minnesota | 66,000 | Turkeys | [6] |
April 1 | Beadle County, South Dakota | 50,600 | Turkeys | [6] |
April 2 | Stearns County, Minnesota | 71,000 | Turkeys | [6] |
April 4 | Stearns County, Minnesota | 76,000 | Turkeys | [6] |
April 7 | Meeker County, Minnesota | 310,000 | Turkeys | [6] |
April 8 | Kingsbury County, South Dakota | 71,900 | Turkeys | [6] |
April 9 | Lyon County, Minnesota | 66,000 | Turkeys | [6] |
April 10 | McPherson County, South Dakota | 55,200 | Turkeys | [6] |
April 10 | McCook County, South Dakota | 54,700 | Turkeys | [6] |
April 11 | Jefferson County, Wisconsin | 189,100 | Chickens | [6] |
April 13 | Swift County, Minnesota | 160,000 | Turkeys | [6] |
April 13 | Stearns County, Minnesota | 76,000 | Turkeys | [6] |
April 14 | Swift County, Minnesota | 154,000 | Turkeys | [6] |
April 14 | Redwood County, Minnesota | 56,000 | Turkeys | [6] |
April 15 | Kandiyohi County, Minnesota | 152,000 | Turkeys | [6] |
April 15 | Stearns County, Minnesota | 67,000 | Turkeys | [6] |
April 15 | Roberts County, South Dakota | 66,600 | Turkeys | [6] |
April 16 | Barron County, Wisconsin | 126,700 | Turkeys | [6] |
April 20 | Osceola County, Iowa | 3,800,000 [lower-alpha 1] | Chickens | [3] |
April 20 | Wadena County, Minnesota | 301,000 | Turkeys | [6] |
April 20 | Kandiyohi County, Minnesota | 61,000 | Turkeys | [6] |
April 21 | Kandiyohi County, Minnesota | 130,400 | Turkeys | [6] |
April 21 | Kandiyohi County, Minnesota | 61,000 | Turkeys | [6] |
April 21 | Stearns County, Minnesota | 53,900 | Turkeys | [6] |
April 22 | Stearns County, Minnesota | 72,500 | Turkeys | [6] |
April 22 | Kandiyohi County, Minnesota | 62,600 | Turkeys | [6] |
April 22 | Kandiyohi County, Minnesota | 62,600 | Turkeys | [6] |
April 22 | Meeker County, Minnesota | 58,900 | Turkeys | [6] |
April 23 | Clay County, Minnesota | 408,500 | Chickens | [6] |
April 23 | Chippewa County, Wisconsin | 56,500 | Turkeys | [6] |
April 23 | Kandiyohi County, Minnesota | 54,300 | Turkeys | [6] |
April 24 | Jefferson County, Wisconsin | 1,031,000 | Chickens | [6] |
April 24 | LaMoure County, North Dakota | 71,500 | Mixed poultry | [6] |
April 24 | Kandiyohi County, Minnesota | 67,000 | Turkeys | [6] |
April 24 | Chippewa County, Minnesota | 64,900 | Turkeys | [6] |
April 27 | Sioux County, Iowa | 1,603,900 | Chickens | [8] |
April 27 | Barron County, Wisconsin | 83,300 | Turkeys | [6] |
April 28 | Sioux County, Iowa | 3,660,000 | Chickens | [9] |
April 28 | Osceola County, Iowa | 258,000 | Chickens | [9] |
April 28 | Steele County, Minnesota | 82,900 | Turkeys | [6] |
April 28 | Kandiyohi County, Minnesota | 50,900 | Turkeys | [6] |
April 29 | Stearns County, Minnesota | 202,500 | Chickens | [6] |
April 30 | Buena Vista County, Iowa | 449,100 | Turkeys | [6] |
April 30 | Barron County, Minnesota | 96,500 | Turkeys | [6] |
May 1 | Buena Vista County, Iowa | 4,910,600 | Chickens | [6] |
May 4 | Madison County, Iowa | 1,495,600 | Chickens | [6] |
May 5 | Wright County, Iowa | 2,821,800 | Chickens | [6] |
May 5 | Nicollet County, Minnesota | 1,102,900 | Chickens | [6] |
May 5 | Barron County, Wisconsin | 182,400 | Turkeys | [6] |
May 5 | Swift County, Minnesota | 151,300 | Turkeys | [6] |
May 5 | Kandiyohi County, Minnesota | 89,100 | Turkeys | [6] |
May 5 | Pipestone County, Minnesota | 72,200 | Turkeys | [6] |
May 5 | Barron County, Wisconsin | 57,200 | Turkeys | [6] |
May 6 | Kandiyohi County, Minnesota | 65,000 | Turkeys | [6] |
May 7 | Sioux County, Iowa | 309,900 | Chickens | [6] |
May 7 | Osceola County, Iowa | 256,000 | Chickens | [6] |
May 7 | Buena Vista County, Iowa | 52,900 | Turkeys | [6] |
May 8 | Wright County, Iowa | 1,106,500 | Chickens | [6] |
May 8 | Sioux County, Iowa | 581,300 | Chickens | [10] |
May 8 | Sioux County, Iowa | 327,900 | Chickens | [6] |
May 8 | Sioux County, Iowa | 303,100 | Chickens | [6] |
May 11 | Swift County, Minnesota | 65,600 | Turkeys | [6] |
May 12 | Dixon County, Nebraska | 1,791,500 | Chickens | [11] |
May 12 | Wright County, Iowa | 966,600 | Chickens | [6] |
May 13 | Hutchinson County, South Dakota | 70,600 | Turkeys | [6] |
May 13 | Yankton County, South Dakota | 70,600 | Turkeys | [6] |
May 14 | Lyon County, Iowa | 390,000 | Chickens | [6] |
May 15 | Dixon County, Nebraska | 1,709,400 | Chickens | [12] |
May 15 | Buena Vista County, Iowa | 903,700 | Chickens | [13] |
May 15 | Sioux County, Iowa | 272,300 | Chickens | [13] |
May 15 | Sioux County, Iowa | 240,000 | Chickens | [13] |
May 18 | Moody County, South Dakota | 642,700 [lower-alpha 2] | Chickens | [6] |
May 18 | Meeker County, Minnesota | 138,800 | Turkeys | [6] |
May 19 | Renville County, Minnesota | 2,045,600 | Chickens | [15] |
May 20 | Sioux County, Iowa | 240,000 | Chickens | [6] |
May 21 | Sac County, Iowa | 100,000 | Turkeys | [6] |
May 26 | Dixon County, Nebraska | 293,200 [lower-alpha 3] | Chickens | [6] |
May 27 | Knox County, Nebraska | 3,000,000 | Chickens | [5] |
May 27 | Adair County, Iowa | 974,500 | Chickens | [6] |
May 27 | Renville County, Minnesota | 95,300 | Turkeys | [6] |
May 28 | Wright County, Iowa | 991,500 | Chickens | [6] |
May 28 | Kandiyohi County, Minnesota | 50,800 | Turkeys | [6] |
June 1 | Wright County, Iowa | 434,800 | Chickens | [6] |
June 1 | Moody County, South Dakota | 52,000 | Turkeys | [6] |
When an infection was confirmed, all birds at the affected farm were destroyed per USDA guidelines. The birds were often culled by foam depopulation through pumping an expanding water-based foam into the barn houses, which suffocates them within minutes. The birds were then composted, usually at the location. [3]
Influenza A virus (IAV) is a pathogen that causes the flu in birds and some mammals, including humans. It is an RNA virus whose subtypes have been isolated from wild birds. Occasionally, it is transmitted from wild to domestic birds, and this may cause severe disease, outbreaks, or human influenza pandemics.
Avian influenza, also known as avian flu, is a bird flu caused by the influenza A virus, which can infect people. It is similar to other types of animal flu in that it is caused by a virus strain that has adapted to a specific host. The type with the greatest risk is highly pathogenic avian influenza (HPAI).
Influenza A virus subtype H5N1 (A/H5N1) is a subtype of the influenza A virus which can cause illness in humans and many other species. A bird-adapted strain of H5N1, called HPAI A(H5N1) for highly pathogenic avian influenza virus of type A of subtype H5N1, is the highly pathogenic causative agent of H5N1 flu, commonly known as avian influenza. It is enzootic in many bird populations, especially in Southeast Asia. One strain of HPAI A(H5N1) is spreading globally after first appearing in Asia. It is epizootic and panzootic, killing tens of millions of birds and spurring the culling of hundreds of millions of others to stem its spread. Many references to "bird flu" and H5N1 in the popular media refer to this strain.
The global spread of H5N1 influenza in birds is considered a significant pandemic threat. While other H5N1 influenza strains are known, they are significantly different on a genetic level from a recent, highly pathogenic, emergent strain of H5N1, which was able to achieve hitherto unprecedented global spread in 2008. The H5N1 strain is a fast-mutating, highly pathogenic avian influenza virus (HPAI) found in multiple bird species. It is both epizootic and panzootic. Unless otherwise indicated, "H5N1" in this timeline refers to the recent highly pathogenic strain of H5N1.
Transmission and infection of H5N1 from infected avian sources to humans has been a concern since the first documented case of human infection in 1997, due to the global spread of H5N1 that constitutes a pandemic threat.
H5 N2 is a subtype of the species Influenzavirus A. The subtype infects a wide variety of birds, including chickens, ducks, turkeys, falcons, and ostriches. Affected birds usually do not appear ill, and the disease is often mild as avian influenza viral subtypes go. Some variants of the subtype are much more pathogenic than others, and outbreaks of "high-path" H5N2 result in the culling of thousands of birds in poultry farms from time to time. It appears that people who work with birds can be infected by the virus, but suffer hardly any noticeable health effects. Even people exposed to the highly pathogenic H5N2 variety that killed ostrich chicks in South Africa only seem to have developed conjunctivitis, or a perhaps a mild respiratory illness. There is no evidence of human-to-human spread of H5N2. On November 12, 2005 it was reported that a falcon was found to have H5N2.
Influenza A virus subtype H7N7 (A/H7N7) is a subtype of Influenza A virus, a genus of Orthomyxovirus, the viruses responsible for influenza. Highly pathogenic strains (HPAI) and low pathogenic strains (LPAI) exist. H7N7 can infect humans, birds, pigs, seals, and horses in the wild; and has infected mice in laboratory studies. This unusual zoonotic potential represents a pandemic threat.
Influenza A virus subtype H7N2 (A/H7N2) is a subtype of the species Influenza A virus. This subtype is one of several sometimes called bird flu virus. H7N2 is considered a low pathogenicity avian influenza (LPAI) virus. With this in mind, H5 & H7 influenza viruses can re-assort into the Highly Pathogenic variant if conditions are favorable.
Influenza A virus subtype H7N3 (A/H7N3) is a subtype of the species Influenza A virus.
H5N8 is a subtype of the influenza A virus and is highly lethal to wild birds and poultry. H5N8 is typically not associated with humans. However, seven people in Russia were found to be infected in 2021, becoming the first documented human cases.
H5N3 is a subtype of the species Influenza A virus.
The global spread of H5N1 in birds is considered a significant pandemic threat.
The global spread of H5N1 in birds is considered a significant pandemic threat.
The global spread of H5N1 in birds is considered a significant pandemic threat.
Fujian flu refers to flu caused by either a Fujian human flu strain of the H3N2 subtype of the Influenza A virus or a Fujian bird flu strain of the H5N1 subtype of the Influenza A virus. These strains are named after Fujian, a coastal province in Southeast China.
The Goose Guangdong virus refers to the strain A/Goose/Guangdong/1/96 (Gs/Gd)-like H5N1 HPAI viruses. It is a strain of the Influenzavirus A subtype H5N1 virus that was first detected in a goose in Guangdong in 1996. It is an HPAI virus, meaning that it can kill a very high percentage of chickens in a flock in mere days. It is believed to be the immediate precursor of the current dominant strain of HPAI A(H5N1) that evolved from 1999 to 2002 creating the Z genotype that is spreading globally and is epizootic and panzootic, killing tens of millions of birds and spurring the culling of hundreds of millions of others to stem its spread.
The global spread of H5N1 in birds is considered a significant pandemic threat.
In the early 2020s, an ongoing outbreak of avian influenza subtype H5N8 has been occurring at poultry farms and among wild bird populations in several countries and continents, leading to the subsequent cullings of millions of birds to prevent a pandemic similar to that of the H5N1 outbreak in 2008. The first case of human transmission of avian flu, also known as bird flu, was reported by Russian authorities in February 2021, as several poultry farm workers tested positive for the virus.
Since 2020, global cases of avian influenza subtype H5N1 have been rising, with cases reported from every continent as of February 2023 except for Australia and Antarctica. In late 2023, H5N1 was discovered in the Antarctic for the first time, raising fears of imminent spread throughout the region, potentially leading to a "catastrophic breeding failure" among animals that had not previously been exposed to avian influenza viruses. The virus involved in the outbreak is classified in H5 clade 2.3.4.4b.
More than 25 million commercial laying hens and pullets in Iowa have been killed by the H5N2 virus or euthanized to prevent the disease from spreading further. One million turkeys also have been destroyed since the first case was confirmed in early April.
That makes 7 million birds that have been or will be destroyed in Nebraska since bird flu became epidemic in the upper Midwest
The H5N2 virus is highly infectious and deadly, meaning up to 3.8 million hens must be destroyed at Sunrise Farms near Harris in Osceola County. An earlier estimate put the number at 5.3 million.
The previous outbreak, reported May 14, involved an egg farm with 1.3 million chickens.